Kentucky bluegrass

ABSTRACT

A variety of Kentucky bluegrass which exhibits good resistance to common lawn grass diseases including leaf spot, leaf rust, stripe smut and powdery mildew, has an attractive, rich, dark green color and a turf-type growth habit.

SUMMARY OF THE VARIETY

This invention relates to a new and distinct variety of Poa pratensis which has been designated P-101 Kentucky bluegrass.

The variety was originated by crossing an upatentedselection identified in our breeding records as Bellevue with Anheuser Dwarf (U.S. Plant Pat. No. 3,135), Bellevue being the seed parent and Anheuser Dwarf the pollen parent. As a result of this breeding, I have produced and asexually propagated by rhizomes, tillers and disseminules, a variety which is distinct from each of its parents and from all other varieties of which I am aware.

Asexual reproduction of P-101 by propagules (tillers and rhizomes) and by disseminules (modified caryopses produced by agamospermy) has consistently produced progeny plants indistinguishable from the mother plant.

The novel characteristics of the P-101 Kentucky bluegrass variety reside particularly in its attractive, rich, dark green color which can be maintained throughout the entire growing season, moderately wide leaf blades, turf-type growth habit, good resistance to common turf diseases including leaf spot, leaf rust, stripe smut and powdery mildew and its ability to produce a high quality turf. Specifically, P-101 exhibits the following unique combination of characteristics:

1. Good resistance to the leaf spot and crown rot disease caused by the fungus, Helminthosporium vagans;

2. Good resistance to the stripe smut disease caused by the fungus, Ustilago striiformis;

3. Good resistance to powdery mildew caused by the fungus, Erysiphe graminis;

4. Good resistance to the leaf rust disease caused by the fungus, Puccinia poae-nemoralis.

5. An attractive, rich, dark green color which can be maintained throughout the entire growing season;

6. Good rhizome and tiller development under turf maintenance producing a turf of moderate density and good horizontal spreading ability.

7. A leafy turf-type growth habit tolerant of moderately close mowing;

8. Moderately wide leaf blades;

9. Large spikelets; and

10. Good turf performance, as evidenced by consistently high performance scores in tests in New Jersey and Ohio.

In comparison with its seed parent, Bellevue, the new variety has wider leaves, larger spikelets, a darker green color, maintains a more leafy turf during late spring and has better resistance to stripe smut and powdery mildew.

In comparison with its pollen parent, Anheuser Dwarf, the new variety has taller, more upright culms and better early spring color.

In comparison with its sister selection, P-72 (U.S. Plant Pat. No. 3,782), the new variety is taller, has fewer panicles and produces a more leafy turf in late spring.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a photograph of a P-101 Kentucky bluegrass plant after completion of anthesis;

FIG. 2 shows a typical mature P-101 panicle; and

FIG. 3. shows an established plot of P-101 Kentucky bluegrass maintained under turf conditions in which the front half has been cut at 3/4 inches, the back half at 13/4 inches.

DETAILED DESCRIPTION OF THE VARIETY

P-101 Kentucky bluegrass (Poa pratensis L.) is perennial with creeping rhizomes forming a moderately dense turf. Culms are quite erect with only a slight bend at lower nodes, tufted averaging 74 cm tall when undisturbed by clipping. Leaves are dark green, averaging 4.2 mm wide; the blades are hairless on both sides, initially folded but then opening out with a boat-shaped apex. Ligules are membranous and covered with fine hairs, edge of collar is fringed in fine hairs. The flag leaf averages 45 mm in length. Panicles at time of anthesis are green, lightly tinged with purple, slightly nodded at the tip, pyrimidal and open averaging 99 mm long. Lower branches are mostly perpendicular to the main panicle axis, lowest cluster of branches usually in a whorl of 3 to 4 (average 3.5). Spikelets are ovate, compressed, 4.7 to 6.8 mm long (average 5.7), usually 4 to 5-flowered (average 4.4), breaking up at maturity beneath each lemna. Glumes persistent, pointed, unequal, rough on the keels; lower mostly 1 -nerved, ovate averaging 3.1 mm long, upper 3-nerved, ovate to elliptic averaging 3.5 mm long. Lemmas overlapping, 5-nerved, oblong or ovate in side view, pointed tip, hair on the keel and nerves to the middle, long fine crinkled hair at the base and on the lower margin. Paleas about as long as the lemmas with 2 rough keels. Grain tightly enclosed in the lemma and palea.

Since environmental conditions such as soil and climate influence morphological characters to some degree, the morphological characteristics will vary somewhat. Morphological characteristics of P-101 are compared with other Kentucky bluegrass varieties in Table 1.

                                      Table 1.                                     __________________________________________________________________________     Morphological comparison of P-101 and other bluegrass varieties at             Adelphia, New Jersey                                                                                                       Number                                                                         of                                                              Number         branches                                                Leaf                                                                               Flag                                                                               of        Panicle                                                                             at                                             Plant                                                                              Plant                                                                               Blade                                                                              leaf                                                                               panicles  erect                                                                               lowest                                                                              Panicle                                   height                                                                             diameter                                                                            width                                                                              length                                                                             per  panicle                                                                             or   panicle                                                                             length                        Variety     cm  cm   mm  mm  plant                                                                               color.sup.1                                                                         nodding.sup.2                                                                       node mm                            __________________________________________________________________________     P-101       74  25   4.2 45   78  1.5  2.0  3.5  99                            P-72        66  26   4.0 47  199  1.5  1.5  3.9  102                           Delta       73  17   2.6 67  196  2.0  1.0  4.8  100                           Geary       80  24   2.9 80  177  3.0  3.0  4.0  134                           Newport     79  30   4.8 77  246  2.5  2.0  4.3  105                           Palouse     79  24   3.0 93  151  3.0  3.5  4.4  92                            Anheuser Dwarf                                                                             67  30   5.1 51  109  3.0  2.5  3.4  96                            Belturf     70  35   3.0 58  201  2.0  2.0  4.0  104                           Fylking                                                                        (U.S. Pat. No. 2887)                                                                       60  34   4.0 68  164  3.5  5.0  4.9  118                           Merion      70  24   4.3 69  280  2.0  1.5  3.5  102                           Pennstar    59  34   3.7 66  132  3.5  4.0  4.5  106                           __________________________________________________________________________      .sup.1 Scale: 0 = green; 5 = purple                                            .sup.2 Scale: 1 = erect; 5 = nodding                                     

The new variety has exhibited consistently high turf performance ratings at New Brunswick, N. J. and Marysville, Ohio. Overall turf performance ratings for P-101 and other bluegrasses are presented in Tables 2 and 3.

                  Table 2.                                                         ______________________________________                                         Turf performance ratings of P-101 and other bluegrass                          varieties at New Brunswick, New Jersey                                         ______________________________________                                                Turf Performance Score                                                         9 = best                                                                Variety  1966    1967    1968  1969  1970  Ave.                                ______________________________________                                         P-101    7.8     8.5     8.4   7.9   7.0   7.9a*                               Anheuser                                                                       Dwarf    7.6     7.3     7.5   6.9   7.6   7.4a                                Fylking  6.9     6.8     8.0   7.6   7.2   7.3a                                Pennstar 6.9     6.8     7.9   7.1   7.2   7.2a                                Belturf  6.2     5.9     7.4   7.0   6.2   6.5b                                Bellevue 6.4     6.7     6.9   5.9   5.7   6.3b                                Merion   6.3     6.1     6.8   4.9   4.1   5.6c                                Delta    4.5     4.2     5.2   4.9   4.5   4.7d                                ______________________________________                                          *Values within a column followed by the same letter do not differ at the       five percent probability level.                                          

                  Table 3.                                                         ______________________________________                                         Relative comparison of P-101 and other bluegrass                               varieties growing under natural shade at Marysville, Ohio.                     ______________________________________                                         Turf quality score 9 = best                                                    Variety May 16    July 1   September 30                                                                               Ave.                                    ______________________________________                                         P-101   7.7       7.7      7.8         7.7                                     P-72    7.9       6.6      6.9         7.1                                     Merion  6.2       6.2      5.7         6.0                                     Fylking 4.7       4.7      4.1         4.5                                     Pennstar                                                                               4.8       4.1      3.0         3.8                                     Park    3.0       4.5      3.3         3.6                                     ______________________________________                                    

The new variety has a dark green color which can be maintained throughout the growing season. Color rating comparisons of P-101 and other bluegrasses grown at Accokeek, Md., are presented in Table 4.

                  Table 4.                                                         ______________________________________                                         Color rating comparisons of P-101 and other bluegrass                          varieties grown at Accokeek, Maryland.                                                Color rating (10 = darkest green)                                                Feb.   Apr.   May  June July Sept.                                                                               Nov.                                Variety  14     1      22   15   22   5    22   Ave.                           ______________________________________                                         P-101    9.0    8.0    9.0  9.0  8.0  8.5  8.0  8.5                            P-72     8.0    8.0    8.0  8.0  9.0  8.0  9.9  8.4                            Sydsport 6.5    6.0    6.0  7.5  8.0  8.0  6.8  7.0                            Windsor  7.0    6.0    5.5  7.0  7.0  8.3  6.5  6.8                            Nu Dwarf 2.0    6.0    6.0  7.0  7.0  8.0  6.5  6.1                            Common                                                                         Kentucky 4.0    7.0    5.0  6.0  7.0  7.0  6.0  6.0                            ______________________________________                                    

The new variety is moderately aggressive with good horizontal spreading ability as shown by measurements presented in Table 5.

                  Table 5.                                                         ______________________________________                                         Aggressiveness of various bluegrass varieties as measured                      by their ability to spread under conditions of close mowing                    and competition from other bluegrasses at New                                  Brunswick, New Jersey.                                                         ______________________________________                                                      Amount of encroachment                                                         into adjacent bluegrass varie-                                    Variety      ties (inches)                                                     ______________________________________                                         P-101        +10.0*                                                            Belturf      + 8.0 a                                                           Bellevue     + 3.0 b                                                           Pennstar     + 2.5 b                                                           Fylking      + 2.5 b                                                           Anheuser Dwarf                                                                              + 2.0 b                                                           Merion       - 1.5 c                                                           Windsor      - 1.5 c                                                           Delta        - 3.0 c                                                           ______________________________________                                          *Values within a column followed by the same letter do not differ at the       five percent probability level.                                          

Comparisons of P-101 and other bluegrasses for resistance to leaf spot and crown rot caused by the fungus Helmintosporium vagans, stripe smut caused by the fungus Ustilago striiformis, powdery mildew caused by the fungus Erysiphe gramins and leaf rust caused by the fungus Puccinia poae-nemoralis are presented in Tables 6, 7, 8, 9, 10 and 11.

                  Table 6.                                                         ______________________________________                                         Relative comparison of leaf spot and crown rot disease                         incidence of P-101 and other bluegrasses at New                                Brunswick, New Jersey.                                                         ______________________________________                                                      percent disease                                                   Variety      damage                                                            ______________________________________                                         P-101          2 a*                                                            Anheuser Dwarf                                                                               2 a                                                              Merion        5 b                                                              Fylking       6 b                                                              Pennstar      6 b                                                              Bellevue     10 b                                                              Belturf      20 c                                                              Delta        70 d                                                              ______________________________________                                          *Values within a column followed by the same letter do not differ at the       five percent probability level.                                          

                  Table 7.                                                         ______________________________________                                         Relative comparison of leaf spot disease incidence                             on P-101 and other bluegrass varieties under natural shade                     at Marysville, Ohio.                                                           ______________________________________                                                 Percent leafspot                                                                 May      July     September                                          Variety   16        1       30        Ave.                                     ______________________________________                                         P-101     20       17        8        15                                       P-72      20       23        9        17                                       Merion    33       23       15        24                                       Fylking   38       37       25        33                                       Pennstar  34       39       40        38                                       Park      59       44       26        43                                       ______________________________________                                    

                  Table 8.                                                         ______________________________________                                         Relative comparison of stripe smut disease incidence                           of P-101 and other bluegrasses at New Brunswick, N.J.                          ______________________________________                                                      Stripe smut infected tillers                                      Variety      per square foot of turf                                           ______________________________________                                         Anheuser Dwarf                                                                                0 a*                                                            Pennstar      0 a                                                              Fylking       0 a                                                              P-101         2 a                                                              Bellevue     11 b                                                              Delta        11 b                                                              Merion       228 c                                                             ______________________________________                                          *Values within a column followed by the same letter do not differ at the       five percent probability level.                                          

                  Table 9.                                                         ______________________________________                                         Reaction of Kentucky bluegrass varieties to powdery                            mildew disease under greenhouse conditions at New                              Brunswick, New Jersey.                                                         ______________________________________                                                          Mildew rating                                                 Variety          9 = most disease                                              ______________________________________                                         A-20             0.0 a*                                                        P-101            0.7 b                                                         Newport          0.8 b                                                         A-34             1.8 c                                                         Sodco            2.0 c                                                         Fylking          3.9 d                                                         Pennstar         4.2 d                                                         Belturf          4.3 d                                                         Merion           6.9 e                                                         ______________________________________                                          *Values followed by the same letter do not differ significantly at the         five percent probability level.                                          

                  TABLE 10.                                                        ______________________________________                                         Relative comparison of powdery mildew disease                                  incidence on P-101 and other bluegrass varieties                               under natural shade at Marysville, Ohio.                                       ______________________________________                                         Variety          Percent mildew                                                ______________________________________                                         P-101            2.7                                                           A-34             6.7                                                           P-72             7.3                                                           Nugget           28.3                                                          Common Kentucky  70.0                                                          Pennstar         80.0                                                          Windsor          86.7                                                          Merion           93.3                                                          ______________________________________                                    

                  Table 11.                                                        ______________________________________                                         Relative comparison of leaf rust disease level for                             P-101 and other bluegrass varieties at Adelphia,                               New Jersey.                                                                    Variety          Rust disease rating*                                          ______________________________________                                         P-101            0.8 a**                                                       Pennstar         1.5 b                                                         Fylking          1.5 b                                                         Prato            2.0 b                                                         Newport          3.5 c                                                         Merion           3.5 c                                                         Vantage          7.5 d                                                         ______________________________________                                           *Rating Scale: 0 = no rust; 9 = disease most severe                           **Values followed by the same letter do not differ significantly at the        five percent probability level.                                          

The new variety is medium late in maturity as indicated by relative comparison of flowering dates presented in Table 12.

                  Table 12.                                                        ______________________________________                                         Date of initiation of anthesis of Kentucky bluegrass                           varieties at Adelphia, New Jersey.                                             Variety             Date flowers first open                                    ______________________________________                                         Kenblue*            May 18 to May 24                                           Delta               May 20    a**                                              Nugget              May 23    b                                                Newport             May 25    c                                                Fylking             May 26    cd                                               Pennstar            May 26    cd                                               Galaxy              May 27    de                                               Majestic            May 27    de                                               Bonnieblue          May 27    de                                               P-101               May 27    de                                               Anheuser Dwarf      May 28    ef                                               Merion              May 29    fg                                               Adelphi             May 30    g                                                Glade               May 30    g                                                Brunswick           June 2    h                                                ______________________________________                                           *Kenblue is a mixture of different bluegrass types.                           **Dates followed by the same letter do not differ statistically at the         five percent probability level.                                           

I claim:
 1. A new and distinct variety of Kentucky bluegrass plant, substantially as shown and described, characterized by good resistance to many important lawn grass diseases, good turf performance, an attractive dark green color, good rhizome and tiller development and moderately wide leaves. 